This SCOR will explore the role of the oxidative modification of diverse targets in the atherogenic process. Although oxidant injury has been implicated in pathogenesis, the process is poorly characterized in integrated systems, such as humans. Recent developments offer novel opportunities to integrate assessment of free radical based modification of protein, lipids and DNA in vivo. A central theme of this proposal is the opportunity to assess the effects of potential prooxidants and antioxidants on these novel biomarkers. A second broad feature of this proposal is the close integration of genomic (A) and proteomic (B) analysis. In Project 1, we shall address the hypothesis that nicotine sustains the endothelial dysfunction observed in chronic smokers and accelerates atherogenesis in the Apobec-l/LDL receptor double knock out mouse (DKO) by acting as a prooxidant integrating biomarkers developed in Projects 2, 3 and 4 and utilizing Cores A and B to relate alterations in gene and protein expression in circulating cells to those in the vasculature. In Project 2, the biophysical and cell biological consequences of fibrinogen nitration will be assessed. As polymorphisms that result in elevated fibrinogen interact with cigarette smoking in the prediction of cardiovascular risk, we shall investigate the effects of nitration on the interaction of fibrinogen with platelets and vascular cells. In Project 3, we shall address the possibility that hyaluronan, a major extracellular matrix protein and its CD 44 receptor may be modified by oxidative stimuli in both model systems and in humans in collaboration with Projects 1 and 5. Again, we shall utilize the resources of the cores to elucidate the modifications that are induced in these targets. In Project 4, we shall characterize further the covalent modifications to DNA resulting from hydroperoxide derived electrophiles; investigate the role of oxygenases in this process; determine from studies in Projects 1 and 5 whether vitamin C administration results in such DNA modifications in vivo and, using the Cores, assess their role in the apoptotic pathway, using endothelial cells as a model system. In Project 5, we shall address the possibility that HDL, inversely associated with cardiovascular risk, may have functional relevance, at least in part, by acting as an endogenous antioxidant. We will investigate the antioxidant potential of HDL components in vitro and by using genetic manipulation of ApoA in mice. We shall also follow progression of plaque burden in humans with electron beam computerized tomography relating HDL to the integrated indices of oxidative stress developed in Projects 1, 2, 3 and 4 as well as the genomic and proteomic analyses developed in the Cores to both the studies in humans and mice. This highly integrated SCOR will broaden consideration of oxidative targets of potential relevance to atherogenesis and utilize a highly integrated series of studies in mice and humans to assess the role of pro- and anti-oxidant interventions on a novel series of biomarkers of oxidant stress in vivo.